What problems are you having with the Dimmer 2s? I have many of these installed, and I don't seem to have any problems. Are your issues known to be specific to the C-7 hub? I have one of the earlier hubs.
One tip about the parameters: Are you aware that you can set any parameters you want using the "Basic Z-Wave Tool" custom driver? (Switch over to that driver temporarily to check/set your parameters, then switch back to the actual driver)
